The Phoenicians seem to have been international middlemen though who started where is debatable. I was looking at tin ingots from the Erme estuary just round the corner from Burgh Island, a tidal (Phoenician?) island in Devon, which are described as knuckle- or H-shaped.
This site http://www.swmag.org/index.php/stories/ ... ary-ingots says rectangles and other shapes and sizes of ingots were found but the H-shaped ingots are considerably smaller and appear to be peculiar to this area.
They look like dung beetles which were sacred to Ancient Egyptians. The beetles may have been as useful to African pastoralists as the earthworm is to English gardeners though the latter don't have to contend with tsetse flies. Dung beetles have an extraordinary (unique?) ability to navigate via the Milky Way which may, or may not, have been regarded as ultra-special by herders.